a = set()
print(a)
type(a)
b = {}
type(b)
c = set('foobar')
print(c)
type(c)
a = {'ddr','ddr1'}
print(a)
print(type(a))
a.add("王源")#
print(a)
a.update("易烊千玺")#
print(a)
a.remove("ddr")#
print(a)
a.discard("ddr1")#
print(a)
a.pop()#随机删除
print(a)
a.clear()#clear:清空元素
print(a)
